The heart is a hollow muscular organ that contracts approx. 100,000 times a day and pumps approx. five liters of blood into the circulation every minute. It is not only characterized by the unique features of muscle tissue specialized to meet the constant physical demands of pumping blood, but also by muscle cells that send spontaneous rhythmic electrical impulses to stimulate contraction. This article gives an overview of the structure of the heart wall and of cardiac muscle tissue.

USMLE™ is a joint program of the Federation of State Medical Boards
(FSMB®) and National Board of Medical Examiners (NBME®). MCAT is a registered
trademark of the Association of American Medical Colleges (AAMC).
None of the trademark holders are endorsed by nor affiliated with Lecturio.